title: Direct measurement of field-free molecular alignment by spatial (de)focusing effects.
abstract: We directly measure the field-free molecular alignment of various room-temperature molecular gases based on alignment-induced spatial focusing and defocusing effects. By imaging the spatial profile of a time-delayed probe pulse with increased and decreased local intensity at the beam center, the parallel and perpendicular molecular alignments are clearly characterized. Meanwhile, the electronic Kerr effect, weak plasma contribution and field-free molecular alignment impact could be distinguished from the measured signals.
authors.affiliation: State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China.
authors.forename: Yahui
authors.initials: Y
authors.lastname: Feng
authors.forename: Haifeng
authors.initials: H
authors.lastname: Pan
authors.forename: Jia
authors.initials: J
authors.lastname: Liu
authors.forename: Cheng
authors.initials: C
authors.lastname: Chen
authors.forename: Jian
authors.initials: J
authors.lastname: Wu
authors.forename: Heping
authors.initials: H
authors.lastname: Zeng